Remote control



R. ALKAN REMOTE CONTROL June 14, 194s.

Filed May 26, 1945 INVENToR. Rob crz af/7l WMZ m z Y A TTOQNEY Patented June 14, 1949 UNITED STATES PATENT OFFICE REMOTE CONTROL Robert Alkan, Locust Valley, N. Y., assigner to Specialties, Inc.

Application May 26, 1945, Serial No. 595,924

Claims. (Cl. S18-31) The present invention relates to remote control apparatus of the type wherein a controlled rotating member at a receiver must follow the continuous or intermittent rotative movements and reversals of a master rotating member at the transmitter, and has for an object to provide a reliable, accurate remote control which will meet the requirements of aircraft use and which can be operated by available direct current Aof relatively low voltage.

Another object is to provide a remote `control giving rotary motion of the follower with high delity to both rapid and slow movements of the master rotor.

Still another object is to provide a rotary remote control in which overrunnng and hunting `are reduced to a minimum.

The nature and objects `of the invention will be better understood from a description of a particular, illustrative embodiment for the pur-poses of which description reference should be had to the accompanying drawings forming a part hereof and in which Figure 1 is an electrical diagram of an apparatus embodying the invention.

Fig. 2 is a transverse, sectional view of the receiver.

Fig. 3 is a view in elevation showing the contacts and slip rings with the front plate and resistance removed.

Fig, 4 is a perspectiveview of the resistance unit.

`The apparatus comprises a transmitter 5 and a receiver (i of which the transmitter may be yoperated by any suitable source as for example, a computer or even by hand and the receiver is `actuated by a reversible follow-up motor 1 under Icontrol `of electrical currents in turn controlled by the transmitter. The transmitter and receiver are of similar construction except that the main shaft `8 of the transmitter can be driven by any suitable mechanism whereas the main shaft 9 of the receiver is arranged to be operated by the follow-up motor. A sensitive, polarized relay I0 controls the electrical circuits to cause the motor to drive in one direction or the other as the rotatable element yof the transmitter leads or lags relative to the rotatable element of the receiver.

A description of the receiver shown in Figs. 2, 3 and 4 will serve as a disclosure lof the transmitter also. In the electrical diagram similar parts of the transmitter and receiver are marked with the same numbers but the parts of the transmit ter are marked with a prime. l

The shaft 9 mounted centrally in the back plate carries a rotatable member -or spider II comprising a pair of contact arms I2 yand I3 positioned at right angles to each other. The arms carry or terminate in contact elements I4 and I5 respectively, which engage the resistance I6 wound on the front plate to provide a flat resistance unit with a substantially smooth surface `presented towards the `rotatable spider. The arms I2 and I3 are insulated from each 4other and are formed at their opposite ends with contacts I8 and I9 engaging respectively pairs of semi-circular contact rings or slip rings 20, 2|, 22 yand 23 all insulated from each other. The resistance |16 is shown as a flat wound coil but it may 'be of any construction which provides a circular contact path for the 4contacts I4 and I5. The resistances are connected to the positive and negative current sources at opposite sides of the circular path of contact so that the voltage is maximum on one side yand minimum on the other side with a gradient between. In the particular form of resistance shown, the voltage gradient is uniform along the length 0f the resistance and the voltage impressed at the c-ontacts during rotation of the spider will vary substantially as the sine and cosine of the angle through which the spider turns. What is more important, however, is the fact that the voltage gradient from one side to the `other Will be the same in both transmitter and receiver with similar paths of contact which conveniently but not necessarily are circular.

The shaft 9 -of the receiver is driven by motor 'I through reduction gearing 25 and 26. The transmitter shaft is controlled in `any suitable way to be Idriven continuously or intermittently in either direction in accordance with the motion to be transmitted.

VAs shown in :the electrical diagram, the followup motor is controlled by a sensitive, polarized relay I0 which operates to connect the motor for forward or reverse driving as may be ynecessary to rotate the spider of the receiver to bring it into synchronism with the spider of the transmitter. The polarized relay includes two principle actuating coils 30 and 3| which for convenience will be termed sine and cosine coils connected to be energized by the circuits which connect the transmitter and receiver elements. In the electrical diagram the spider of the transmitter is shown as turned at an angle a at a given moment during operation from what, for convenience, will be termed as the zero position. The spider `of the receiver is at the same instant acting through the cosine coil tends to hold the polarized relay in one position in which `the reversing switch is held in the position shown.

During rotation of the spider of the receiver to reduce the lead of the transmitten, the -current will be reduced until the two spiders are in a psition of synchronisrn and the angle e is reduced to zero. The sine coil 3I is similarly energized by current flowing from the resistance I6, through contact arm I3, semi-circular sine coil, slip ring 2'0, arm I3?, to the resistance- I-6 of the transmitter. The two coils are soarranged that `they add their ampere turns to c0-4 operate to actuate the polarized relay in one di.- rection or the other. It will be noted thatin eachcase the operating conductor connected to the slip ring 29. or 22 is also connected tothe semi-A circular slip ring 21| or 23. of the transmitter but since the contact arms are not in engagement with either of the slip rings of the transmitter, this connection is immaterial; In another position of the spiders, a different set ofslip rings will be in operation.

If the polarized: relay were actuated only bythe sine and cosine coils shown andi described,

there would be a considerable tendency for the motor to overrun and hunt. In ordery to. avoid this, a third auxiliary coil, (called a differential coil) 33, is provided in the polarized relay andi arranged to add algebralcally its action to theaction of bot-h coils, 30. and 3I. differential coilopposes the othercoils during op eration. The differential. coil is shown as connected across the terminals of the motor sothat as the current inthe motor circuit reverses, the

current in the diierential coil reverses, When the receiver spider approaches a position ofI synchronism with the spider of the transmitter, the

current in the active coils 3'0- andf 3-I willl be reduced nearly to zero and the differential' coil willthen act with suicient power to reverse the polarized relay thereby reversing the motor slightly before the spider of the receiver reaches the position of synchroni'sm. The circuit of the follow-up motor can be adjusted to determine the frequency of reversal of this motor when the two spiders are perfectly synchronized and the motor is merely reversing without turni-ng over a substantial number of" turns in either direction. The circuit may be such, for example, that the motor will reverse eighteen times per secon-d.

By analysis of the power in the sir-1e and cosinecoils 30 and 3l' it will be notedf thatl the voltagein these coils graduallybuilds up from zero when there is no 1ead, when the two spiders are in perfect synchron-ism, to considerable power when there is a substantial leadl.

responding arms I2- and I2v ofthe transmitterslip.v ring 20, the

Ordinarily, the- The powerv therefore is approximately proportional to thev"circuit connecting and receiver are in a position of small lead, as near the top of the diagram, Fig. 1, the current in the cosine coil will be low. However, at that time, the current in the sine coil through the arms I3 and I3 will be relatively at its maximum. Accordingly, in usual operation in all positions, the power available for operating the polarized relay is the sum of two electrical currents one of which is relatively high whenthe other is low and their sum is always sufficient to operate the relay reliably.

It is to be noted that there are positions in which there is no current through one or the other of the sets of arms which work together as when the arm I2 is on one side of the vertical in the electrical diagram and the arm I2 is on the other side. of the vertical. This is immaterial because at such time, the other set of arms will bein a position to provide maximum power through the other coil. It is contemplated that at no time will the lead of one spider over the other spider be more than and the follow-up.- motor is chosen with suflicient power and speed to maintain such operation.

Overrunning is practically eliminated by the circuits shown. As the follower approaches the position of equilibrium, the differential coil is excited by a current proportional to the voltage across the follow-up motor and therefore sub-- stantially proportional to its speed wherefore themotor reverses with practically no overrun.

The foregoing description of a particular selected embodiment isl illustrative merely and is not intended as defining the limits of the invention. It will be understood that various changes can be made inthe structure of parts and thev circuit arrangement without departing from the principles of' the invention as deiined in the appended claims.

I claim:

1. A direct current remote controlv comprising similar resistances at transmitter and receiverstations respectively, each resistance being formed to provide a circular contact path and adapted to be connected to positive and negativecurrent sources at opposite sides of the circular contact path, at each station a pair of angularly-A related, rotatably mounted contact arms insulated from each other engaging said resistances a polarized relay having three coils, an electric motor controlled by the polarized relay connected to drive he pair of arms at the receiver station, an electric circuit connecting the -rst coil to similar arms of both pairs, a second electric a second coil to the other' similar arms, and a third electric circuit connecting the third coil to receive currentl proportional' to, and of the sign of, the voltage across the motor terminals, said rst and second coils cooperatingas actuating coils to insure actuation of the polarized rela-y in accordance with the relative posi.- tions of the rotatable contact arms at the trans'- mitter and receiver stations and said third coil" acting in opposition to the actuating coils to inhibit overrunning of the motor;

2; A direct current remote control comprisingY similarresistances at transmitter and receiver stations respectively, each resistance -being formed to provide a circular Contact path and adapted to be connected to positive and negative current sources at opposite sides of the circular contact path, at each station a pair of angularly related, rotatably mounted contact arms` insulated from each4 other, each arm engagingl the resistance along saidl circular path, a reversible follow-up motor connected to a source of constant voltage and arranged to rotate the pair of contact arms at the receiver station continuously or intermittently in either direction, a relay controlling said follow-up motor, said relay having principal actuating coils connected with the contact arms to be energized by current of one sign or the other as the contact arms at the transmitting station move in one direction or the other from a position of synchronism Iwith the contact arms at the receiver station and having an auxiliary actuating coil connected to receive current proportional to and of the sign of the voltage across the motor terminals and arranged to oppose said principal actuating coils and tending to cause reversal of the relay as the -contact arms at the receiver station approach a position of synchronism with the arms at the transmitter station.

3. A direct current remote control comprising resistances at the transmitter and receiver stations, a rotatable member at each station having two angularly related contacts engaging the resistances, a reversible follow-up motor arranged to drive the rotatable member at the receiver station intermittently or continuously in either direction, a relay electrically connected to both rotatable members to control the motor in accordance with the relative positions of the rotatable members, said relay including a differential coil connected across the motor terminals tending to cause reversal of the relay when the motor is operating in either direction.

4. A direct current remote control comprising similar, at wound resistances at transmitter and receiver stations, each resistance being formed to provide a circular contact path and adapted to be connected to positive and negative current sources at opposite sides of the circular contact path, a, rotatable member at each station having two angularly related contacts insulated from each other and engageable with the respective resistance along the circular path a reversible follow-up motor connected to drive the rotatable member at the receiver station intermittently or continuously in either direction, a polarized relay controlling said motor having three energizing coils, one electrical circuit connecting one coil and similar contacts of the two rotatable members, a second electrical circuit connecting a second coil and the other set of similar contacts of the rotatable members and a third circuit connecting the third coil to the motor terminals, said first and second coils being arranged to act to move the relay in the same direction and the third coil being arranged to oppose such movement to prevent overrunning.

5. A direct current remote control comprising similar resistances at the transmitter and receiver stations respectively, each resistance being formed to provide a circular contact path and adapted to be connected to positive and negative current sources, at each station a pair of angularly related rotatably mounted contact arms insulated from each other, each arm engaging the resistance along said circular path, a reversible follow-up motor connected to a source of constant voltage arranged to rotate the pair of contact arms at the receiver station in either direction, a reversing relay controlling said follow-up motor, a polarized relay controlling said reversing relay and having two principal actuating coils connected to receive current from the contact arms to energize the relay in one direction or the other as the contact arms at the receiving stations lead or lag with respect to the contact arms at the transmitter station and having a third coil connected to receive current from across the motor terminals and arranged to act in opposition to said principal coils to cause actuation of the polarized relay and therefore of the reversing relay as the rotatably mounted contact arms at the receiver station approach but before they reach the position of synchronism with the contact arms at the transmitter station.

ROBERT ALKAN.

REFERENCES CITED The following references are of record in the iile of this patent:

UNITED STATES PATENTS Number Name Date 1,268,712 I-Iarle June 4, 1918 2,383,942 Patin Sept. 4, 1945 FOREIGN PATENTS Number Country Date 550,426 Great Britain Jan. 7, 1943 

